The present invention relates to the physical housing or packaging of the class of electrical apparatus known as ground fault circuit interrupters (GFCI). More particularly, the invention relates to a module having terminal means for direct connection of the wires of a power cord from an electrical appliance, or the like, and a plug for insertion in a standard jack or receptacle, with GFCI means housed within the module and interposed between the terminals and plug.
The possibility of injury and/or damage which is inherent in the operation of any electrical system of significant magnitude has led to the provision of various protective devices. Among these are the class of electrical apparatus which has come to be known as ground fault circuit interrupters (GFCI). In general, such apparatus senses and/or responds to a condition in a line carrying electrical current which indicates a presently or imminently dangerous condition, such as the presence of a current path other than the intended path of normal operation. Response to the sensed dangerous condition may be in the form of alarm actuation and/or opening the line (interrupting the circuit) between the source of power and the load.
In general, GFCI equipment has been provided in a form suitable for mounting in the conventional circuit breaker panel box at the input to the electrical distribution system of a building, in conjunction with electric receptacles in ordinary household or trade size junction boxes, and in separate, transportable boxes or housings having receptacle means for detachable connection of the line cord from a load and additional means for connecting the box to a power source. Although the latter type of GFCI may be moved from place to place, and thus used in locations not provided with permanently installed GFCI devices, there is always the possibility of situations where an electrical appliance or other load must be connected to a power source and ground fault protection should be provided but is not available.
The principal object of the present invention is to provide GFCI protection which is connected directly to the associated piece of equipment (load) in an essentially permanent manner, whereby ground fault protection is provided simply by connecting the load to the power line.
More specifically, it is an object of the invention to provide a module having both terminals for connection of the wires of a line cord from a load and a standard plug for insertion in a receptacle connected to a power source with a GFCI device interposed therebetween and housed within the module.
A further object is to provide a plug-in module for connection at the end of a line cord and enclosing a ground fault protective device in an essentially waterproof housing.
Another object is to provide a plug-in module having terminals for connection of the wires of a line cord within a first compartment and a complete GFCI protective device within a second compartment of housing means providing separate, essentially water-tight capability for the two compartments.
A still further object is to provide a plug-in module adapted to receive the end of a line cord in sealing engagement with water-proof housing means which also encloses GFCI equipment and which will accommodate line cords of various diameters by changing only a single component.
Still another object is to provide GFCI equipment in a novel physical configuration, facilitating its assembly with housing means to form a module incorporating a plug for insertion in a standard electrical receptacle and adapted to be packaged and sold as a separate item for installation on the end of a line cord by anyone having basic familiarity with cords and plugs, not necessarily a skilled electrician.
Other objects will in part be obvious and will in part appear hereinafter.